This invention relates to electric motor lead screw driven linear actuators, and more particularly to such actuators for adjustable seat mechanisms particularly adapted for marine use on recreational watercraft such as cabin cruisers, speed boats, sport boats, fishing skiffs and the like.
The continued development and upgrading of recreational watercraft has seen the introduction of various power driven convenience accessories including power actuated adjustable seats for helmsman, passenger and aft trolling/fishing station use. There also is a continuing need to improve such systems from the standpoint of such parameters as ease of installation on standard marine seating, vertical profile, load carrying capacity, non-binding operation, economy of manufacture, reliability, and service life under adverse marine environmental conditions.
Typically, the gear drive and associated heavy-duty slide and rail used for mounting the seats are provided as separate assemblies, which in turn leads to additional costs both in manufacture and in assembly and installation on the watercraft. In addition, in some prior art the load of the seat is impressed gravitationally on the gear drive and/or motor as well as on the associated dual slides and rails, thereby leading to track and/or carriage binding and even lock-up from stress-induced distortion, excessive wear, premature system failure and seat load limitations. Some systems now incorporate metal to metal contact in the carriage or slide assembly which leads to sticking and jamming from salt water corrosion and dirt. Other systems suffer from excessive play and rattling creating irritating noise when under way in the watercraft as they vibrate harmonically with the engine vibration imparted to the watercraft. Typically, the seat slide assemblies are installed as dual parallel tracking rails and carriage/slides wherein cocking is a problem, particularly when supporting extra-wide dual person side-by-side type seats, leading to drive jamming, motor failure and/or fuse blowing. Prior art assemblies also often require excessive vertical clearance between the seat bottom and the seat mounting area in order to fit the seat slide drive assembly, rendering the unsightly drive unduly visible and less stable in use.
Accordingly, among the objects of the invention are to provide an improved electric seat slide and actuator system that overcomes one or more of the foregoing problems of prior art marine electric seat slide and actuator systems and that is improved from the standpoint of (1) economy of manufacture, (2) versatility and flexibility in design, different travel lengths, thrust capacities and carriage travel speed, (3) overall height as installed, (4) ease of installation on standard marine seating, (5) unitization of gear drive and heavy duty slide and rail, (6) isolation of the weight load of the seat and the passengers sitting on the seats from the gear drive and/or motor for actuating the same, (7) reduction of frictional resistance to seat slide travel, (8) reduction or elimination of excessive play in the seat mounted on the actuator system, (9) dual seat carriage tracking capability along slightly misaligned parallel tracks, (10) ability to handle off-center loading without hang-up and jamming, (11) ease of installation as a complete assembly for mounting of the seat on the actuator system, (12) capability to resist lock-up or racking when a seat is moved against a travel resistance force applied unevenly or to one side only, or when weight-loaded unevenly and off-center as by an occupant sitting on either extreme end of the seat, (13) elimination of the need to cut holes in the mounting seat box on the watercraft in order to accommodate an excessively high system assembly profile, and/or (14) elimination of the need for a special mounting system.